The present invention relates to print head designs for impact printers, and more particularly to improved type chases for reciprocating stamping machines.
One particular category of impact printer, to which the present invention relates, is the reciprocating stamping machine. This machine incorporates one or more "typeholding chases", each of which houses a plurality of type "sorts" to define the image. In one particular version of this machine, the type sorts consist of elastomeric members which include formed backings to engage the type housing. These devices typically utilize a high speed reciprocating motion of such print heads to create hundreds of impressions per minute. Such typeholding chases should therefore firmly engage the individual type elements to prevent accidental release due to normal machine motions, incidental vibrations, etc. A suitable design of such print heads should also facilitate removal and interchange of type sorts by the user in order to change the impression.
An article in the Jan. 18, 1982 issue of Design News, "Spring-loaded Pucks Lock Type in Place", by Bernard Gill of Kiwi Coder Corporation, Wheeling, IL, discloses a typeholding chase of this general description. The print head disclosed in this reference suffers the shortcoming that it requires the use of tools in the interchange of type sorts, in order to adjust internal mechanisms which are part of the disclosed system.
Accordingly, it is a principal object of the invention to provide an improved typeholding chase for impact printers. A related object is to provide a typeholding chase which is particularly suited to high speed stamping machines using reciprocating print heads.
Another object of the invention is to achieve a print head design which firmly locks type sorts in place during machine operation. It is a related object that the print head incorporate mechanisms which will not release type sorts during machine operation, but will simplify the removal of these sorts when this is desired.
A further object of the invention is that such print head designs facilitate the interchange of type sorts to change the print head impression. A related object is to avoid the need for tools or special manipulation of mechanisms within the print head for type sort interchange.